【摘要】：葉輪類復雜零件加工是數(shù)控技術研究領域的重點,其加工難點主要體現(xiàn)在葉片截面薄、曲面形狀復雜、刀軌干涉嚴重等方面。與傳統(tǒng)加工方式相比,側銑加工具有工作效率高、表面光潔度好、加工成本低等優(yōu)點,五坐標數(shù)控側銑加工葉輪葉片已經(jīng)成為一種趨勢。側銑加工的刀具通常以圓柱刀、圓錐刀等為代表的回轉面刀具。葉輪類零件葉片曲面多為非可展直紋面,側銑加工時存在著原理性誤差。鑒于此,本文以圓錐刀為主要研究對象,探索適用于回轉面刀具的共性的刀位規(guī)劃方法。論文根據(jù)給出的葉輪葉片曲面的離散數(shù)據(jù)點并結合葉片曲面結構特點及CATIA功能特點,采用三次準均勻B樣條插值技術,建立葉輪葉片曲面的數(shù)學模型及實體模型,為后續(xù)工作奠定基礎。利用粒子群優(yōu)化算法對圓錐刀的側銑刀位規(guī)劃問題進行了研究。將刀軸上一點到圓錐面的距離定義為該點對應的當量半徑,給出單個刀位的最優(yōu)判定條件即刀軸上各點到直紋面的距離與該點當量半徑之差的平方和為最小,從而將刀具包絡面向直紋面的逼近問題轉化為每個刀位最優(yōu)判定條件的實現(xiàn)問題。給出基于粒子群優(yōu)化算法的求解最優(yōu)刀軸軌跡面的實現(xiàn)過程。結合剛體運動學及實驗設計方法,提出另外一種刀軸軌跡的生成策略。將刀具軸線上諸點在設計曲面上的法向投影點的集合定義為法向映射曲線,并給出一種理論特征點的計算方法,進而提出另外一種單刀位最優(yōu)性判定條件,即每瞬時法向映射曲線與特征線實現(xiàn)最小二乘逼近。利用剛體運動學方法將刀軸位姿用3個回轉與3個平移運動參數(shù)描述,建立起單刀位優(yōu)化條件與6個運動參數(shù)的非顯性的函數(shù)關系。采用拉丁超立方的試驗設計方法求解獲得最優(yōu)的刀軸軌跡面。
[Abstract]:The machining of complicated parts of impeller is the focus of numerical control technology. The difficulties of machining are mainly reflected in thin blade section, complex curved surface and serious interference of cutter track, and so on. Compared with traditional machining methods, side milling has many advantages, such as high efficiency, good surface finish and low processing cost, etc. It has become a trend for 5-axis NC side milling to machining impeller blades. Side milling tools are usually cylindrical knives, conical cutters, etc. as the representative of the rotary surface tools. The blade surface of impeller parts is mostly non-developable and straight, and there is a principle error in side milling. In view of this, this paper takes the conical cutter as the main research object, and explores the common tool position planning method suitable for the rotary surface cutter. According to the discrete data points of impeller blade surface and the characteristics of blade surface structure and CATIA function, the mathematical model and solid model of impeller blade surface are established by using cubic quasi-uniform B-spline interpolation technique. Lay the foundation for follow-up work. Particle swarm optimization (PSO) algorithm is used to study the side milling cutter position planning of conical cutter. The distance from one point on the cutter axis to the cone surface is defined as the equivalent radius corresponding to the point, and the optimal judgment condition of a single cutter position is given, that is, the sum of squares of the difference between the distance from each point on the cutter axis to the surface of the straight ridge and the equivalent radius of the point is the smallest. Thus, the approach problem of tool envelope facing straight surface is transformed into the realization of the optimal condition of each tool position. The process of solving the optimal tool path surface based on particle swarm optimization algorithm is presented. Combined with rigid body kinematics and experimental design method, another tool path generation strategy is proposed. The set of normal projection points of all points on the tool axis on the design surface is defined as a normal mapping curve, and a method for calculating the theoretical characteristic points is given, and then another criterion for determining the optimality of single tool position is proposed. That is, every instantaneous normal mapping curve and feature line achieve least square approximation. By using rigid body kinematics method, the position of cutter axis is described by three rotation and three translational motion parameters, and the non-explicit functional relationship between the optimization condition of single tool position and six motion parameters is established. The optimal tool path surface is obtained by using the Latin hypercube experimental design method.
【學位授予單位】：大連交通大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TG54

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本文編號：2218253